Scientist/writer David Horton describes it as a mistake that we have talked about “species evolving” when discuss evolution. He considers this “an easy mistake to make, and you can see why we made it, but it has proved fatal.” He argues that biologists have unwittingly confused the creationists with talk of species evolving.
So if I was writing biology text books for use in Texas or Kentucky or Missouri schools I think I would join their education authorities in demanding that the word evolution not be mentioned. Instead I would put all of my effort into explaining speciation. Show how that original bacterium could become 2, 4, 8, 20, 30, 60 … species. Could become, even after losing tens of thousands of species along the way, the tens of thousands of species, including humans, chimps, and bacteria, we see today.
Instead of focusing on natural selection, which Horton considers “too obvious,” he would stress the importance of allopatric speciation:
Allopatric speciation is simply this – if one part of a species becomes separated by a geographic barrier (a mountain range forms, sea level rises, a desert comes into being, a river changes course, a landslide falls, a continent moves, a glacier extends), and stays separate long enough, then its members will no longer be able to breed with the other part of the population and it will therefore have become a different species. Doesn’t matter why it becomes different – just an accumulation of mutations might do the trick . . .
It's a subtle point, but one worth making. The notion of species "evolving" presumes that "species" are distinct in some absolute (as opposed to subjective) sense. In fact, "species" are merely the categories that biologists have created to simplify the sorting and studying of the many different critters that occupy our planet. Such a mental model opens the door for creationists to mock the notion that, say, mammals evolved from amphibians (or, in creationist lingo, 'that a frog could turn into a human'). By contrast, speciation would seem to be a fact that even most creationists would acknowledge.
I've often thought of this post. The more I consider it, the more I think that David Horton is correct. Evolution seems to suggest an endpoint in that it seems to look backwards, which troubles many people that one can get to an endpoint without sentience. When one speaks of speciation, though, one is talking of branching that goes wherever it goes. No particular destination in mind, and we just happened to be one of those destinations. I've started substituting "speciation" for "evolution" and it seems to confuse, then reframe the topic in a way that seems, somehow, more neutral.